Lighting Calculator

This foot candle calculator gives you the optimal illumination level for each room in your home and determines how many light fixtures you need to achieve it.

Find Your Required Illumination


How many lumens per sq foot do I need?

In the first step of your calculations, you need to choose the type of area and activity that you want to illuminate.

Simply select one of the options from the list, and our lighting calculator will automatically determine the optimal level of illumination in lux or foot-candles (that is, how much light should be incident on the surface). Intuitively, ambient light in the bedroom shouldn't affect our preparations for sleep time and won't be as intensive as the light required for sewing.

The next thing you need to determine is the illuminated area. In the case of a bedroom or a bathroom, it will simply be the room's total area. If you're trying to figure out LED lighting for your kitchen counter, the illuminated area will be calculated as the length of the counter multiplied by its width.

Once you know all these values, the foot-candle calculator will determine how many lumens you need. We use the following equation:

lumens= lux * area

You can use illumination units of lux or foot candles. If you want to recalculate between these units, remember that one foot-candle equals 10.764 lux10.764 lux.

How do I calculate the lighting for a room?

To calculate the lighting of an area:

  1. Measure the dimensions of the surface of interest.
  2. Compute the area of the surface.
  3. Calculate the lumens required using the formula
    lumens = lux × area

The lux is a measurement of the received light per area unit. The lumens is a unit that measures the amount of light emitted by a light source.

What is the difference between lumen and lux?

The lumen is a unit of luminous flux; lumens correspond to the amount of light emitted by a source, such as a lightbulb or a candle, regardless of direction.

Lux is used to measure the amount of light shining on a surface. A high amount of lux corresponds to a brightly lit surface.

Lux and lumens are related by the formula lumens = lux * area